Photonuclear production of medical isotopes^(62,64)Cu using intense laser-plasma electron source

摘要

^(62,64)Cu are radioisotopes of medical interest that can be used for positron emission tomography(PET)imaging.Moreover,64Cu hasβ−decay characteristics that allowfor targeted radiotherapy of cancer.In the present work,a novel approach to experimentally demonstrate the production of ^(62,64)Cu isotopes fromphotonuclear reactions is proposed in which large-current laser-based electron(e−)beams are generated fromthe interaction between sub-petawatt laser pulses and near-critical-density plasmas.According to simulations,at a laser intensity of 3.431021 W/cm2,a dense e−beamwith a total charge of 100 nCcan be produced,and this in turn produces bremsstrahlung radiation of the order of 1010 photons per laser shot,in the region of the giant dipole resonance.The bremsstrahlung radiation is guided to a natural Cu target,triggering photonuclear reactions to produce themedical isotopes ^(62,64)Cu.An optimal target geometry is employed to maximize the photoneutron yield,and ^(62,64)Cuwith appropriate activities of 0.18 GBq and 0.06 GBq are obtained for irradiation times equal to their respective half-livesmultiplied by three.The detection of the characteristic energy for the nuclear transitions of ^(62,64)Cu is also studied.The results of our calculations support the prospect of producing PET isotopes with gigabecquerel-level activity(equivalent to the required patient dose)using upcoming high-intensity laser facilities.